Timing belt replacements are bread and butter at the dealership. It's one of those repairs that no one turns down, since everyone knows someone who neglected it and ended up spending $4000 on a new engine. Book time on the Accord V6 was something like 5 hours, but I knew master techs who could knock them out in 45 minutes flat. The first time I witnessed it, it cost me a 12-pack of beer on a bet.
TLDR: When all you do is one job on one version of a car you should be good at it (totally over-simplifying what a dealership tech does, but by and large a dealership tech only works on one brand of car. That must be nice, I have to work on pretty much every brand but some of the high end Euros, and am expected to be able to do a job in the same time a tech who only does that job can do).
That's pretty impressive, I guess I should say that when we do a timing belt job at our shop we also do a water pump replacement. It isn't too bad to do, but requires removal of the cam gear toward the radiator to be removed so that the rear metal timing cover can be removed and the water pump extracted and replaced. The last T-Belt I did the rear cam seal was leaking so I had my dad help me remove that cam gear. When it broke loose due to our positioning he actually broke my nose (not the first time I've broken it) by slamming his elbow into it. We bill out 5 hours as that is book time to replace the water pump, even on a hybrid engine which is way more involved.
Sounds like that dealership is scamming customers as time for the a simple T-Belt replacement, including replacing the tensioner and idler's is 3.4 hours. I've watched super experienced "master techs" (do you mean ASE or dealer certified?) do these jobs and I seriously doubt any tech could replace the timing belt and all associated bits and have the car up and running and out the door in 45 minutes. Timer starts as soon as the tech picks up the RO, because that is how we are "paid" be it flat rate or bonus.
Maybe this just shows my inexperience with Asian vehicles. I mean I'm replacing the vacuum pump on an 08 Beetle which bills out at 8+ hours because according to the book you need to R&R the transmission, but with my knowledge and experience I know that is bullshit. So the first shop the customer took their car too said they didn't want to do it because of that so the customer took it to our shop instead. I happen to have a lot of experience doing this repair, and as there are no labor times for the job if you don't remove the trans, I estimated 2 hours. The shop then charged 3 hours for it, my boss tacking on that extra hour to pay for my experience in the matter. I pulled the car in at 4.40 today. By 4.55 I was almost half way done with the job.
That being said a vacuum pump is much easier then a timing belt and water pump. Honda / Acura timing belts are usually simply a time consuming one man job, but Toyota / Lexus timing belts almost certainly require two people (I've done a few solo), because the front cam doesn't want to stay times, and will roll forwards or backwards required it to be manually held in place while putting on the timing belt. Then after replacing the water pump, tensioner, idlers and installing the belt and cover, then you need to bleed the cooling system, take it on a test drive, get it fully hot to burp the system, wait for it to cool off and then top off the coolant level. At least that is how you need to do things to get it right, which most dealership tech's aren't too concerned about in my experience. The turn over is so high in my area most of them are just looking to make a quick buck before they are fired.
